1. Field of the Invention
The invention is a device to protect the insulators on the towers of high voltage electrical transmission lines.
2. Background
On high power transmission lines, the insulators prevent the lines from contacting the metal towers which support the lines. Contract between the tower and the transmission line results in a short circuit disrupting electric service. Many birds find transmission lines and towers to be irresistible perches. Bird droppings are highly conductive. Over a period of time, the accumulation of bird droppings will conduct a current over the insulators causing a short circuit.
Large birds of prey pose a greater threat to transmission lines than the majority of birds. These predators use the towers as hunting perches. Typically when these birds leave their perches, they face into the wind and defecate a long stream of fecal material. The stream can often bridge the insulators and short circuit the transmission line. In the western United States, repair crews travel hundreds of miles to repair the damage caused by bird droppings.
U.S. Pat. No. 6,812,400 discloses a dielectric device which encloses a power line at the point of contact with an insulator to protect from a short circuit.
U.S. Pat. No. 5,291,707 discloses a conical cover to prevent birds from landing on a flue gas exhaust stack.
U.S. Pat. No. 5,615,524 discloses a multi-pronged cover for the mast of a sailing ship to prevent birds from perching on the mast head.
U.S. Pat. No. 5,873,324 discloses a bird guard which fits over and under an insulator on an electric pole to protect the insulator from bird droppings.
U.S. Pat. No. 2,414,732 discloses an electrical protection device which surrounds an insulator. The device includes a sheet of insulating material which is thick enough to prevent birds from pecking through the material to the insulator.
U.S. Pat. No. 6,730,852 discloses a flexible polymer cover for an electrical power line that fits above an insulator. The cover protects the insulator from bird droppings.
U.S. Pat. No. 6,005,196 discloses a hinged cylindrical guard activated by a trigger mechanism. When activated the guard closes to surround a transformer bushing terminal to prevent wildlife from shorting the circuit.
None of the above patents disclose devices of sufficient size to protect the series of insulators used on high power electrical transmission lines.
None of the above patents disclose devices designed to prevent birds from perching on electrical transmission towers directly above insulators.
None of the above patents disclose a device to frighten birds away from the sections of a tower containing insulators.